Name clash for unamed template arguments.

Author: MaxSagebaum

regression-tests/test-results/gcc-13/pure2-variadics.cpp.output

@@ -1,20 +1,16 @@
-pure2-variadics.cpp2:21:10: error: ‘R’ has not been declared
-pure2-variadics.cpp2:17:20: error: declaration of template parameter ‘T’ shadows template parameter
-pure2-variadics.cpp2:16:10: note: template parameter ‘T’ declared here
-pure2-variadics.cpp2:21:10: error: ‘R’ has not been declared
-pure2-variadics.cpp2:27:20: error: declaration of template parameter ‘_’ shadows template parameter
-pure2-variadics.cpp2:26:10: note: template parameter ‘_’ declared here
-pure2-variadics.cpp2:17:33: error: declaration of template parameter ‘T’ shadows template parameter
-pure2-variadics.cpp2:17:13: note: template parameter ‘T’ declared here
-pure2-variadics.cpp2:17:63: error: expansion pattern ‘T’ contains no parameter packs
-pure2-variadics.cpp2:17:66: error: template argument 1 is invalid
-pure2-variadics.cpp2:17:59: error: too many template-parameter-lists
-pure2-variadics.cpp2:22:13: error: ‘R’ has not been declared
-pure2-variadics.cpp2:22:60: error: expansion pattern ‘_’ contains no parameter packs
-pure2-variadics.cpp2:22:63: error: template argument 1 is invalid
-pure2-variadics.cpp2:22:56: error: too many template-parameter-lists
-pure2-variadics.cpp2:27:33: error: declaration of template parameter ‘_’ shadows template parameter
-pure2-variadics.cpp2:27:13: note: template parameter ‘_’ declared here
-pure2-variadics.cpp2:27:63: error: expansion pattern ‘_’ contains no parameter packs
-pure2-variadics.cpp2:27:66: error: template argument 1 is invalid
-pure2-variadics.cpp2:27:59: error: too many template-parameter-lists
+pure2-variadics.cpp2:17:20: error: declaration of template parameter ‘UnnamedTypeParam1’ shadows template parameter
+pure2-variadics.cpp2:16:10: note: template parameter ‘UnnamedTypeParam1’ declared here
+pure2-variadics.cpp2:27:20: error: declaration of template parameter ‘UnnamedTypeParam1’ shadows template parameter
+pure2-variadics.cpp2:26:10: note: template parameter ‘UnnamedTypeParam1’ declared here
+pure2-variadics.cpp2:17:53: error: declaration of template parameter ‘UnnamedTypeParam1’ shadows template parameter
+pure2-variadics.cpp2:17:13: note: template parameter ‘UnnamedTypeParam1’ declared here
+pure2-variadics.cpp2:17:98: error: ‘_’ was not declared in this scope
+pure2-variadics.cpp2:17:99: error: expected parameter pack before ‘...’
+pure2-variadics.cpp2:17:102: error: template argument 1 is invalid
+pure2-variadics.cpp2:17:95: error: too many template-parameter-lists
+pure2-variadics.cpp2:27:49: error: declaration of template parameter ‘UnnamedTypeParam1’ shadows template parameter
+pure2-variadics.cpp2:27:13: note: template parameter ‘UnnamedTypeParam1’ declared here
+pure2-variadics.cpp2:27:94: error: ‘_’ was not declared in this scope
+pure2-variadics.cpp2:27:95: error: expected parameter pack before ‘...’
+pure2-variadics.cpp2:27:98: error: template argument 1 is invalid
+pure2-variadics.cpp2:27:91: error: too many template-parameter-lists

regression-tests/test-results/pure2-variadics.cpp

@@ -16,15 +16,15 @@ template<typename ...Ts> class x;
 template<int ...Ts> class y;
 
 #line 16 "pure2-variadics.cpp2"
-template<typename ...UnnamedTypeParam1> class t0;
+template<typename ...UnnamedTypeParam1_16_14> class t0;
 
 
 #line 21 "pure2-variadics.cpp2"
 template<auto ...T> class t1;
 
 
 #line 26 "pure2-variadics.cpp2"
-template<auto ...UnnamedTypeParam1> class t2;
+template<auto ...UnnamedTypeParam1_26_14> class t2;
 
 
 //=== Cpp2 type definitions and function declarations ===========================
@@ -56,18 +56,18 @@ template<int ...Ts> class y {
 };
 
 // Discard type name pack expansion
-template<typename ...UnnamedTypeParam1> class t0 {
-  public: template<int UnnamedTypeParam1> [[nodiscard]] static auto f() -> cpp2::i32;
+template<typename ...UnnamedTypeParam1_16_14> class t0 {
+  public: template<int UnnamedTypeParam1_17_7> [[nodiscard]] static auto f() -> cpp2::i32;
 };
 
 // Discard template type pack expansion
 template<auto ...T> class t1 {
-  public: template<int UnnamedTypeParam1> [[nodiscard]] static auto f() -> cpp2::i32;
+  public: template<int UnnamedTypeParam1_22_7> [[nodiscard]] static auto f() -> cpp2::i32;
 };
 
 // Discard typename and template type pack expansion
-template<auto ...UnnamedTypeParam1> class t2 {
-  public: template<int UnnamedTypeParam1> [[nodiscard]] static auto f() -> cpp2::i32;
+template<auto ...UnnamedTypeParam1_26_14> class t2 {
+  public: template<int UnnamedTypeParam1_27_7> [[nodiscard]] static auto f() -> cpp2::i32;
 };
 
 template<typename ...Args> auto left_fold_print(std::ostream& out, Args const& ...args) -> void;
@@ -93,13 +93,13 @@ auto main() -> int;
     template <int ...Ts> [[nodiscard]] auto y<Ts...>::func() -> auto { return (0 + ... + Ts);  }
 
 #line 17 "pure2-variadics.cpp2"
-  template <typename ...UnnamedTypeParam1> template<int UnnamedTypeParam1> [[nodiscard]] auto t0<_...>::f() -> cpp2::i32 { return 0;  }
+  template <typename ...UnnamedTypeParam1_16_14> template<int UnnamedTypeParam1_17_7> [[nodiscard]] auto t0<_...>::f() -> cpp2::i32 { return 0;  }
 
 #line 22 "pure2-variadics.cpp2"
-  template <auto ...T> template<int UnnamedTypeParam1> [[nodiscard]] auto t1<T...>::f() -> cpp2::i32 { return 0;  }
+  template <auto ...T> template<int UnnamedTypeParam1_22_7> [[nodiscard]] auto t1<T...>::f() -> cpp2::i32 { return 0;  }
 
 #line 27 "pure2-variadics.cpp2"
-  template <auto ...UnnamedTypeParam1> template<int UnnamedTypeParam1> [[nodiscard]] auto t2<_...>::f() -> cpp2::i32 { return 0;  }
+  template <auto ...UnnamedTypeParam1_26_14> template<int UnnamedTypeParam1_27_7> [[nodiscard]] auto t2<_...>::f() -> cpp2::i32 { return 0;  }
 
 #line 30 "pure2-variadics.cpp2"
 template<typename ...Args> auto left_fold_print(std::ostream& out, Args const& ...args) -> void{

source/to_cpp1.h

@@ -4262,9 +4262,8 @@ class cppfront
         //-----------------------------------------------------------------------
         //  Handle type parameters
 
-        if (n.declaration->is_type()) {
-            assert( is_template_parameter );
-            printer.print_cpp2("typename ", identifier_pos);
+        // Common template naming
+        auto emit_template_name = [&]() {
             if (n.declaration->is_variadic) {
                 printer.print_cpp2(
                     "...",
@@ -4273,12 +4272,19 @@ class cppfront
             }
 
             if (identifier == "_") {
-                printer.print_cpp2( "UnnamedTypeParam" + std::to_string(n.ordinal), identifier_pos );
+                printer.print_cpp2( "UnnamedTypeParam" + std::to_string(n.ordinal) + "_"
+                                    + labelized_position(n.declaration->identifier->get_token()),
+                                    identifier_pos );
             }
             else {
                 printer.print_cpp2( identifier, identifier_pos );
             }
+        };
+        if (n.declaration->is_type()) {
+            assert( is_template_parameter );
+            printer.print_cpp2("typename ", identifier_pos);
 
+            emit_template_name();
             return;
         }
 
@@ -4291,15 +4297,8 @@ class cppfront
         if (is_template_parameter) {
             emit( type_id );
             printer.print_cpp2(" ", type_id.position());
-            if (n.declaration->is_variadic) {
-                printer.print_cpp2("...",identifier_pos);
-            }
-            if (identifier == "_") {
-                printer.print_cpp2( "UnnamedTypeParam" + std::to_string(n.ordinal), identifier_pos );
-            }
-            else {
-                printer.print_cpp2( identifier, identifier_pos );
-            }
+
+            emit_template_name();
             return;
         }